Shield gaskets are used in combination with shields to provide isolation from electromagnetic interference (EMI) for printed circuit board (PCB) and other components of measurement instruments. For example, vector and scalar network analyzers, spectrum analyzers, and other measurement instruments used in communication systems design and testing include multiple components that must be isolated from one another and that must be isolated from an external environment. FIG. 1 illustrates one example of a shield 10 for use in separating components of a vector network analyzer (VNA). The shield comprises a shield bottom 30 including a plurality of cavities or pockets 32 within which components of the VNA are arranged. As shown, the shield bottom can comprise an aluminum block into which pockets are milled, each being sized and shaped based in part on the component to be held within the pocket and the frequency of signals generated or passing through the component. The shield further comprises a shield top 20 that is mated with the shield bottom to encapsulate the components.
Due to imperfections in the mating surfaces of the shield top and shield bottom, gaskets are used to improve isolation. Shield gaskets can minimize cross-talk and susceptibility to EMI, and thereby maximize performance and reliability in smaller form factors. Present shielding gaskets include Form-in-Place (“FIP”) gaskets which resemble toothpaste squirted on the mating surface of a shield bottom in selected areas, or Formed gaskets which are analogous to a head gasket on an internal combustion engine. Both techniques for applying the gasket are expensive when high isolation is required, time consuming, and require complicated rules for component layout within the shield to enable application of the gasket material.